The present invention relates to a novel electrical switching system. More particularly, the present invention relates to an electrical switching system, particularly for medium voltages, of the type having two bus bars which can be electrically connected by a coupling switch, with the coupling switch performing the connections of loads and power for a plurality of input and output terminals, each of which is connectable with both bus bars via respective disconnect switches.
Switching systems form the nodes of electrical networks for the transmission and distribution of electrical energy. In these nodes, one or a plurality of lines feeding in energy and one or a plurality of load terminals can be connected together. The switching devices here serve the purpose of establishing the electrical connections and of switching operational and/or short-circuit currents. In the past, it has been the custom to include a load or power disconnect switch in each line that is to be connected or disconnected.
The development in switching systems and switching devices is characterized, inter alia, by noticeable cost pressure. Proposals have therefore been made to perform the switching tasks in a system comprised of a plurality of output terminals and/or input terminals with a reduced number of switching devices.
In Federal Republic of Germany Patent application Ser. No. K 11405, published Aug. 9th, 1956, it is proposed to employ a double bus bar system having a coupling switch connected between the bus bars as the central circuit breaker for all input and output terminals of the switching system. Circuit breakers are then no longer necessary in the individual input and output lines and only two disconnect switches leading to the bus bars from each terminal are required. By appropriate control, in time synchronism, of the two disconnect switches of one line and the central coupling switch, loads can be connected and disconnected, with the actuation of the disconnect switch occurring each time in the currentless state. Before and after a switching action, the coupling switch is open. The drawback of such a switching system, and of such a method of actuation, is that five switching actions are required for a disconnection or a connection. Short-circuit disconnects, which must occur very quickly, cannot be effected with this actuation method because of this drawback. For that reason, the cited patent application provides fuses in each output line and in each input line to take over the rapid short-circuit disconnection.